Using Friends as Sensors to Detect Global-Scale Contagious Outbreaks Garcia-Herranz, Manuel ; Moro, Esteban ; Cebrian, Manuel ; Christakis, Nicholas A. ; Fowler, James H. Abstract Publication: PLoS ONE Pub Date: April 2014 DOI: 10.1371/journal.pone.0092413 Bibcode: 2014PLoSO...992413G